1. Field of the Invention
The present invention relates to an optical semiconductor device processing a signal from a photodiode. More precisely, the present invention relates to a PIN photodiode sensor capable of preventing malfunction.
2. Related Background Art
Optoelectronic integrated circuits in which a photodetector and a circuit coupled to the photodetector are integrated on the same semiconductor substrate have recently drawn attention. A PIN photodiode sensor using a PIN photodiode as a photodetector in such an optoelectronic integrated circuit is well known.